The N5030 is rather old. So old that if you were to blindly choose a current generation laptop it will be guaranteed to be more power than the Dell.
The HP 450 G1 has a "standard" Intel dual core CPU. The i5-4200m can reach up to 3.1GHz and it comes with the integrated Intel HD 4600 graphics core. It is actually not bad considering that Intel did not really start to focus on integrated graphics performance until 2010. By "standard" I mean the CPU draws more power than a ULV (ultra low voltage) CPU, but because of that it has a higher clock speed.
The Toshiba Satellite S55-B5266 uses Intel's dual core i7-4510u CPU. The "u" means this is a ULV CPU so get better battery compared to the i5-4200m assuming all other hardware in both laptops...